Cylinder-head combustion chamber



May 6, 1930. A. TAUB ,7

CYLINDER HEAD coMBus TIoncHmBE'R Filed Sept 21, 1927 2 Sheetsr-Sheet lgwuvmtfom J52 Jam;

May 6, 1930. A. TAUB CYLINDER HEAD COMBUSTION CHAMBER Filed Sept. '21,1927 2 Sheets-Sheet 2 m gwuemto a J [21 721265 Patented May 6,

* UNITED STATES [PATENT OFFICE ALEX TAUB, OF DETBbI'I, MICHIGAN,ASSIGNOR TO GENERAL MOTORS CORPORATION, OF DETROIT, MICHIGAN, ACORPORATION OF DELAWARE CYLINDER-HEAD COMBUSTION CHAMBER Applicationfiled September 21, 1927. serial No. aaLo'za.

This invention relates to the combustion chambers of internal combustionreciprocating engines and is particularly applicable to engines in whichthe combustion space communicating with each cylinder. bore lies whollor approximately within a space that Wonk? be bounded by an extension ofthe internal surface of the cylinder bore; it is particularly applicableto engines of the so-called over-head valve type.

Harshness or smoothness of an internal combustion engine depends uponthe rate of pressure rise in the combustion chamber during a combustionperiod, and detonation depends upon the temperature of the unburnedportion of the burning gas. It has been ascertained that rate ofpressure rise and temperature of the last gas to burn during acombustion period can be controlled to -a considerable extent bycombustion chamber form and the relative location of the point ofignition in the chamber in engines of L-head type, wherein aconsiderable volume of the combustion chamber is oif-set'laterally fromthe cylinder bore in order to provide room for valves at one side of thecylinder.

It is an object of this invention to apply. to over-head valve or otherengines having the combustion space over the piston, the principlesfound effective in controlling rate of pressure rise and detonationproducing temperatures in L-head engines.

The invention comprises a cylinder having a combustion chamber notoffset materially from the cylinder bore, of contour and proportionscalculated to reduce the maximum rate of pressure rise toward the end ofthe burning period, and to conduct heat away from that portion ofthecharge that is last to burn so rapidly as to keep it below thtemperature at which it detonates.

In the accompanying drawings in which like reference characters indicatelike parts throughout the several views:

Fig. 1 is a cross section through an engine cylinder embodying thisinvention;

Fig. 2 is a plan view of a head casting belonging to a cylinder blockshown in section In in Fig. 1, a portion of the casting being shownblock; 11 a head casting; 12 a piston adapted valves; 18 one of thepoppet valves (in this in section one plane normal to the c linder axesas indicated by the line22 of ig. 3;

Fig. 3 is an elevation of a portion of a head casting of the form shownin Fig. 2, a art being shown in section on a plane inclu 'ng thecylinder axes, as indicated by the line 33 of Fig. 2, and

Fig. 4 is a view of the underside of a fragment of the head castingshown in the other views.

The particular engine illustrated in the drawing is a four-cylinderengine having the cylinder bores arranged upright in line or in tandemrelation. The combustion chamber illustrated is, of course, applicableto reciprocating internal combustion en ines, whatever may be theposition of the c hnder how axes with respect to a horizonta plane.

Therefore, in referrin to the combustion chamber and valves, asiaeingabove and over the piston or cylinder bore, it is meant that they areopposed to the working face of the piston in w atever angular positionthe cylmders may be disposed and are confined approximately within aspace bounded by the extension of the wall of the cylinder bore beyondthe working face of the piston.

the drawing, 10 indicates a cylinder to reciprocate in cylinder bore 13;17 the combustion chamber over the piston; 14 the usuai cam shaft; 15one of the valve push rods operated by the cams on the cam shaft; 16 oneof the rocker arms for unseating the case an intake valve) forcontrollin a port of communication between the cham lier and a manifold(not shown) 19 a stem attached to said valve andpressed upon by saidrocker arm to 0 en the'valveand 20 a coil spring such as- 1s generallyused for closing the valve. The drawing shows a'four-cylinder engine inwhich ad acent cylinders communicate with a common intake pocket as isindicated at 21. Each exhaust valve .ort communicates by a singlepassage 22 wit an exhaust manifold (not shown);

The combustion chamber 17 is disposed substantially over or above theworking surface 1 of the plston 12. Although shown 1n the il- 100lustrated embodiment as of somewhat great cross sectional area than thecylinder bore, or over-hanging it, the overhang is slight and a is notsuch as to substantially widen the head or cylinder block ascomparedwith what is customary in the over-head valve type of engine.The presenceor absence of overhang as shown is not'material to theinvention and depen'dsmainly on the compression and extent of valvemovement required. The combustion chamber 17 comprises a thin space.

I at 23 where the area of wall surface to volume is relatively largeshortly after the instant of firing when the piston is at or near theend of its compression stroke. At the opposite side of the chamber 17from the thin space 23 there is a firing or ignition bay 24, ofl-setfrom the chamber as" shown in an upward direction. Tapped into thisoff-set portion or firing bay 24 is a spark plug 25, theignitionpomts'bein therefore at considerable distance from te space 23.In the form shown,

flame travel, which isprogressive from the point of ignition, has toproceed around the corner 24 formed by the boundary wall ofbayc24 andthe main portion of the chamber 17. By thetime the flame front reachesthe distant (with reference to the ignition point) side of the chambercontaining the thin space 23, there will be no unburned gas exceptingthat in front of the flame in the space 23 and that lying along thereentrant wall 26 which divides the layer of unburned gas in contactwith itand causes the gas to flow laterally in opposite directions sothat the unburned gasis smoothly deflected, glves up heat to thereentrant wall, and flows without eddying into the relativel thin space23. Thus the last of the gas to e burned will have heat extracted fromit by the large cooling surface in 1 contact with it as compared withthe volume.

The temperature of the last gas to burn will,

therefore, be kept below the temperature at which it detonates undercompressions considerably higher than is customary in automobileengines.

' As indicated at-27 the roof of the combustion chamber immediately infront of (as into the space 23.

The form of. combustion chamber illustrated and described enables thesame results to be obtained in an over-head valve engine as have beenobtained in-L- head engines as regards smoothness of operation andabsence of detonation. By inspection of Fig. 1, it may be imagined thatthe typical combustion chamber of an L-head engine has been bent at anangle of 90 degrees, the valve ports having been shifted from theunderside of the overhanging portion to a position in the roof of thechamber where the valves of over-head valve engines are usually placed.The usual over-head valve type of engine has the combustion chamber socompact that it is difficult to locate the point of ignition in such aposition that the rate of pressure rise can be slow enough to preventthat harshness which occurs when the charge burns too quickly. By

reducing the space between the working face tially free from detonationand harshness,

even though using compressions considerably higher than the normalcompressions in gasoline automobile engines of today. i

I claim: I 1. An engine cylinder having-a combustion chamber providedwith a portion having intake and exhaust ports disposed in itsi'oof overthe cylinder bore, an ignition bay ofl'set upward from the portedportion at one side of I the axis of the cylinder bore, and'a thincooling space opposite the ignition bay at the other side of the axis ofthe cylinder bore, said cooling-space having a large ratio of wallsurface to included volume, relative to the other portions of thechamber, for the purpose of maintaining the last. unburned portion ofthe burning gas below the temper-. ature at which detonation takesplace.

' 2. An engine cylinder as defined in claim 1 in which the thin coolingspace lies between the top of the piston and the roof ofthe chamber whenthe piston is at the end of its compression stroke.

3. An engine cylinder having a combustion chamber rovided with a portionhaving intake and exhaust ports disposed in itsroofover the cylinderbore, an ignition bay ofiset upwards from the ported portion at one sideof the axis of the cylinder bore and a thin cooling space opposite theignition bay at the other side of the axis of the cylinder bore, theside wall of the ported portion of the chamber adjacent the entrance tothe cooling space having a reentrant surface facing the ignition bay. 04. An engine cylinder as defined 1n clamii 3 in which the height of theported portion of the chamber increases adjacent the reentrant side wallwhereby to afford an increased expansion space for the gases beingforced toward the cooling space by themoying flame front.

5. An engine cylinder having a combustion chamber provided with intakeand exhaust ports in the roof over the cylinder bore, an igmtion bayoflset upward from the ported portion at one side of the axis of thecylinder bore and a thin cooling space opposite 5 the ignition bay atthe other side of sald axis;

said cooling space having a large ratio of' wall surfaceto includedvolume relative to the other portions of the chamber and said portedportion increasing in volume adjacent w to the entrance to the coolingspace.

.6. An engine cylinder having a combustion chamber comprising a portionof relatively great depth and small ratio of wall surface to mcludedvolume and a cooling space connecting therewith of relatively smalldepth and large ratio of wall space to included volume; said portion ofrelatively great depth having intake and exhaust ports communicatingtherewith; a sparking device in said portion of relatively great depthdisposed ad'acent the side oppos1te the cooling space, sai portion ofrelatively great depth increasing in volume adjacent to vthecommunication between it and said coolin space.

In testimony whereo I afiix my signa ture. a

. ALEX TAUB.

